This invention relates to a method and apparatus for inhibiting smearing of printed data, and more specifically to inhibiting smearing of machine readable characters printed by a laser imaged electrophotographic printer on checks which will be passed through automatic reader/sorters to process the check.
Most people today have a personal checking account or a savings account through which they can write checks in order to transfer, or obtain money. In order to keep track of these checks, each check is typically coded with a machine readable number along the lower edge of the check. These checks are processed through reader/sorters, such as an IBM 3890, or a Burroughs 9190, in which the checks travel at speeds of about 300 inches per second. A single check may go through the reader/sorters several times during processing.
The check, and the printed account numbers, are passed by numerous drive rollers, belts and detection heads as they are processed. The contact with these various machine elements can cause physical damage to the checks, as well as smearing of the printed data on the checks. The machine readers which detect the account numbers printed on the checks are very sensitive so that even slight smears on the printed numbers can cause an inability to machine read the check. Because of the large number of checks processed, even a small percentage of unreadable checks can amount to significant numbers, and correspondingly significant delays and costs in processing of the checks.
The recent advent of laser printers has enabled banks to print check blanks while a customer is waiting. Thus, customers opening a new checking account can receive a supply of personalized checks for their new account, rather than the standard, nondescript checks which were previously issued until the more personalized checks could be obtained from the printer.
The data printed via non-impact printers which deposit the print on top of the paper, is more subject to smearing than checks printed by other processes. Such non-impact printers include laser electrophotographic printers, thermal transfer printers, ion deposition printers, ink jet printers, and magnetographic printers. Processing of checks printed by a non-impact printers thus leads to an unusually high percentage of checks which smear and thus cannot be adequately processed by conventional reader/sorters.
There is thus a need to reduce the smearing tendency of printed data printed by non-impact printers. This need is especially acute for data that must be machine readable, such as printed numbers on checks. The present invention selectively applies a minute amount of a selected protective coating to inhibit smearing of the printed data.
Processing paper through non-impact printers and copies probably deposits negligible amounts of lubricant on the paper as from contact with rollers treated with silicone releasing agent to prevent sticking, as from contact with Teflon (registered trademark for fluorocarbon polymers including polytetrafluorethylene and fluorinated ethylene-propylene resins) impregnated transport rollers and guide rollers, as from contact with rollers which become coated with the fuser oil used in the printing process, and as from dripping oil and silicone lubricants. To the extent previous devices may have inadvertently and unintentionally placed a material or oil on the surfaces of paper during processing, that inadvertent coating is believed to be on the order of a few micrograms per print, which is not believed sufficient to act as a protective coating as described in this invention. In short, any inadvertent, residual coating placed on the paper or the printed data from the operating equipment, is not sufficient to prevent smearing of the printed data.